Three-dimensional models are used to assist in the placement or use of a device when such placement or use is not easily observable or practical. For example, in medical procedures, three-dimensional models are used to assist in the placement and use of medical devices for the diagnosis or treatment of patients. An example of such a medical procedure carried out with the assistance of a three-dimensional model is the use of a catheter to deliver radio frequency (“RF”) ablation to form lesions that interrupt abnormal conduction in cardiac tissue, thus terminating certain arrhythmias in the heart.